U.S. patent number 5,153,272 [Application Number 07/555,636] was granted by the patent office on 1992-10-06 for curable mixes of fluoroelastomers containing bormine or iodine and of organic peroxides.
This patent grant is currently assigned to Ausimont S.r.l.. Invention is credited to Graziella Chiodini, Attilio LaGostina, Michele Merenda, Anna Minutillo, Ezio Montessoro.
United States Patent |
5,153,272 |
Chiodini , et al. |
October 6, 1992 |
Curable mixes of fluoroelastomers containing bormine or iodine and
of organic peroxides
Abstract
There are described mixes, which are curable by using radical
intermediates, are based on fluoroelastomers containing bromine or
iodine, exhibit, during curing, a low emission of toxic vapors of
methyl bromide or iodide and are characterized in that they
contain, as cross-linking agents, peroxides having the following
formulas: ##STR1## wherein the substitutents from R.sub.1 to
R.sub.17 have the significances defined in the specification.
Inventors: |
Chiodini; Graziella (Saronno,
IT), LaGostina; Attilio (Spinetta Marengo,
IT), Merenda; Michele (Frugarolo, IT),
Minutillo; Anna (Milan, IT), Montessoro; Ezio
(Spinetta Marengo, IT) |
Assignee: |
Ausimont S.r.l. (Milan,
IT)
|
Family
ID: |
11179417 |
Appl.
No.: |
07/555,636 |
Filed: |
July 23, 1990 |
Foreign Application Priority Data
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|
|
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Jul 24, 1989 [IT] |
|
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21277 A/89 |
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Current U.S.
Class: |
525/345;
525/326.3; 525/387; 525/375 |
Current CPC
Class: |
C07C
409/16 (20130101); C08K 5/14 (20130101); C08K
5/14 (20130101); C08L 27/12 (20130101) |
Current International
Class: |
C08K
5/14 (20060101); C08K 5/00 (20060101); C07C
409/00 (20060101); C07C 409/16 (20060101); C08C
019/04 (); C08F 008/00 () |
Field of
Search: |
;525/387,326.3,345,375 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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553191 |
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Feb 1958 |
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CA |
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0208353 |
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Jan 1987 |
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EP |
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1208487 |
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Jan 1966 |
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DE |
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3925743 |
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Feb 1990 |
|
DE |
|
838963 |
|
Jun 1960 |
|
GB |
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1028235 |
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May 1966 |
|
GB |
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Other References
Hawley's Condensed Chemical Dictionary-Eleventh Edition-p.
133..
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Primary Examiner: Schofer; Joseph L.
Assistant Examiner: Sarofin; N.
Attorney, Agent or Firm: Stevens, Davis, Miller &
Mosher
Claims
We claim:
1. Curable mixes based on fluoroelastomers containing bromine
and/or iodine in the polymeric chain, comprising organic peroxides
as radical cross-linking agents, characterized in that the
peroxides are selected from the monoperoxides of formula: ##STR11##
wherein: R.sub.1, R.sub.6, like or different from each other, are
C.sub.2 -C.sub.4 alkyls;
R.sub.3, R.sub.4, like or different from each other, are C.sub.1
-C.sub.4 alkyls;
R.sub.2, R.sub.5, like or different from each other, are C.sub.1
-C.sub.4 alkyls, phenyls, phenyls substituted by C.sub.1 -C.sub.4
alkyls;
and the bisperoxides of formula: ##STR12## wherein R.sub.7 is
C.sub.1 -C.sub.6 alkylene, C.sub.2 -C.sub.6 alkenylene, C.sub.2
-C.sub.6 alkynylene, phenylene;
R.sub.8, R.sub.9, R.sub.10, R.sub.11, like or different from one
another, are C.sub.1 -C.sub.3 alkyls;
R.sub.13, R.sub.15, like or different from each other, are C.sub.2
-C.sub.4 alkyls;
R.sub.12, R.sub.14, R.sub.16, R.sub.17, like or different from one
another, are C.sub.1 -C.sub.4 alkyls;
provided that, when R.sub.7 is phenylene R.sub.8, R.sub.11, like or
different from each other, are C.sub.2 -C.sub.4 alkyls.
2. The mixes according to claim 1, wherein the peroxide is
bis(1,1-dimethylpropyl)peroxide.
3. The mixes according to claim 1, wherein the peroxide is
bis(1,1-diethylpropyl)peroxide.
4. The mixes according to claim 1, wherein the peroxide is
bis(1-ethyl-1-methylpropyl)peroxide.
5. The mixes according to claim 1, wherein the peroxide is
1,1-diethylpropyl, 1-ethyl-1-methylpropyl-peroxide.
6. The mixes according to claim 1, wherein the peroxide is
2,5-dimethyl-2,5-di-ter.amylperoxy-hexane.
7. The mixes according to claim 1, furthermore containing from 0.1
to 1 part by weight of benzothiazole or derivatives thereof.
8. The mixes according to claim 1, furthermore containing from 0.1
to 2 parts by weight of N-phenylmaleimide.
Description
BACKGROUND OF THE INVENTION
The present invention relates to mixes based on fluoroelastomers
containing Br or J, additioned with particular organic peroxides,
which exhibit, during curing, a low emission of toxic vapors of
methyl bromide or iodide.
The cure with organic peroxides of the fluoroelastomers containing,
as cure sites, bromine or iodine atoms along the polymeric chain
and/or at the end of said chain is broadly known.
In such fluoroelastomers, bromine or iodine are introduced into the
elastomer macromolecule by using, during the polymerization step,
brominated or iodidated comonomers such as, in particular,
fluorobrominated olefins, brominated or iodidated fluorovinyl
ethers or by using, in the polymerization itself, brominated or
iodidated compounds as chain transfers.
In the peroxide cure of said elastomers there are utilized, in
general, organic peroxides of the aliphatic type, either saturated
or unsaturated, such as e.g.:
2,5-dimethyl-2,5-di(ter.butylperoxy)hexine-3
2,5-dimethyl-2,5-di(ter.butylperoxy)hexane, which give rise, in the
curing process, to the formation of methyl radicals. These
radicals, by combination with bromine or iodine contained in the
fluoroelastomer, form methyl bromide or iodide, which are highly
toxic volatile products and, as regards iodide, also a
cancerogenous product.
Therefore, while the peroxide curing of fluoroelastomers containing
Br or I permits to obtain cured articles having improved stability
to steam and to other aggressive agents as compared with the
articles obtained through a ionic curing, it is apparent, on the
other hand, that said peroxide curing involves a serious hazard for
the health of the operators entrusted with the processing of said
elastomers.
Furthermore, it is not possible to avoid the drawback caused by
said harmful emissions merely by using peroxides which do not
release at all or release only little amounts of methyl radicals
during their decomposition, because said peroxides could not cure
at all or only weakly cure said fluoroelastomers. That is apparent,
for example, when using organic perketalic peroxide of formula:
##STR2## which, by decomposition, prevailingly provides ethyl
radicals and only little amounts of methyl radicals, but which is
not capable of curing the fluoroelastomers containing bromine or
iodine.
DISCLOSURE OF THE INVENTION
Thus, it is an object of the present invention to substantially
reduce or to eliminate the harmful emissions of methyl bromide or
iodide, which occur during the radical curing, of fluoroelastomers
containing Br or I, without, however, modifying the good
rheological properties of the vulcanizate.
It has now been found that it is possible to substantially reduce
the formation of the above-said toxic products by using particular
organic peroxides, not only without jeopardizing the cure trend and
results, but, conversely, improving the cure rate and the
cross-linking yield.
It has furthermore been found that it is possible to further reduce
or eliminate the methyl bromide or iodide emission if, in
combination with said particular peroxides, little amounts of
organic additives, to be specified hereinafter, are utilized.
By consequence, the object of the present invention is represented
by curable mixes based on fluoroelastomers containing bromine
and/or iodine in the polymeric chain, which comprise organic
peroxides as radical cross-linking agents, and are characterized in
that the peroxides are selected from the monoperoxides of formula:
##STR3## wherein: R.sub.1, R.sub.6, like or different from each
other, are C.sub.2 -C.sub.4 alkyls;
R.sub.3, R.sub.4, like or different from each other are C.sub.1
-C.sub.4 alkyls;
R.sub.2, R.sub.5, like or different from each other, are C.sub.1
-C.sub.4 alkyls, phenyls, phenyls substituted by C.sub.1 -C.sub.4
alkyls;
and the bisperoxides of formula: ##STR4## wherein R.sub.7 is
C.sub.1 -C.sub.6 alkylene, C.sub.2 -C.sub.6 alkenylene, C.sub.2
-C.sub.6 alkynylene, phenylene;
R.sub.8, R.sub.9, R.sub.10, R.sub.11, like or different from one
another, are C.sub.1 -C.sub.3 alkyls;
R.sub.13, R.sub.15, like or different from each other, are C.sub.1
-C.sub.4 alkyls;
R.sub.12, R.sub.14, R.sub.16, R.sub.17, like or different from one
another, are C.sub.1 -C.sub.4 alkyls;
provided that, when R.sub.7 is phenylene, R.sub.8, R.sub.11, like
or different from each other, are C.sub.2 -C.sub.4 alkyls.
A further object of the present invention is curable positions
based on fluoroelastomers containing Br and/or I, which comprise,
besides the peroxides of formula (I) and/or (II), also little
amounts, generally ranging from 0.1 to 1 part by weight for 100
parts of rubber (p.h.r.) of benzothiazole and derivatives thereof,
preferably 2-mercaptobenzothiazole and its salts, in particular
zinc salts, mercaptobenzothiazole disulphide (MBTS),
morpholine-2-benzothiazole-sulphenamide, of 0.1-2 p.h.r. of
N-phenyl maleimide (NPM) or derivatives thereof.
By the further use of little amounts of benzothiazole or its
derivatives it is possible to obtain a complete suppression, during
curing, of the methylene bromide and/or iodide, while retaining the
good character of the vulcanizate prepared by using the peroxides
of formula (I) and/or (II), with the additional advantage due to
the increase of the time required by scorching to occur (scorching
time), what results in a higher processing safety without affecting
the cross-linking rate.
As fluoroelastomers containing bromine or iodine atoms as cure
sites it is possible to cite, for example, the CH.sub.2
.dbd.CF.sub.2 copolymers with CF.sub.3 --CF.dbd.CF.sub.2 and,
optionally, also with C.sub.2 F.sub.4, and the C.sub.2 F.sub.4
copolymers with perfluorovinylethers, containing little amounts of
bromine or iodine, which are introduced by copolymerizing a little
amount of brominated or iodidated monomer as the brominated
olefins, the perfluorobromoalkyl-perfluorovinylethers, or also by
the use of chain transfers, consisting of bromoalkyl or iodoalkyl
compounds.
The peroxides of formula (I) or (II) are known in part, while in
part they have been originally synthesized as the peroxides:
bis(1,1-diethylpropyl) peroxide (S 173);
bis(1-ethyl-1-methylpropyl) peroxide (S 176);
1,1-diethylpropyl,1-ethyl-1-methylpropyl-peroxide (S 185);
2,5-dimethyl-2,5-di-ter.amylperoxy-hexane (S 179);
which form a further object of the present invention.
The amounts of peroxides of formula (I) or (II), which are
contained in the mixes according to the present invention,
generally range from 1 part to 6 parts by weight for 100 parts of
elastomer (p.h.r.) and in particular from 1.5 to 3 p.h.r.
Said peroxides, besides substantially reducing the emission of
toxic methyl bromide and/or iodide by at least 90% and, in a few
cases, by more than 95%, permit to obtain the following
advantages:
increase by 20% to 150% in the cross-linking rate at 180.degree.
C.,
in a few cases, increase in the cross-linking yield at 180.degree.
C.,
improvement in the detach of the article from the mold.
The peroxides can be also utilized in the preparation of mixes
carried on inert fillers, such as e.g. calcium carbonate or silica
or mixtures thereof, which makes easier the utilization thereof and
permits to avoid the drawbacks caused by their volatility.
The mixes based on fluoroelastomers containing bromine and/or
iodine according to the present invention, comprise, besides
organic peroxide and, optionally, benzothiazole, derivatives
thereof or N-phenylmaleimide, the conventional ingredients utilized
in the curable mixes, such as carbon black and other reinforcing
fillers, peroxide curing coagents (for example triallyl
isocyanurate), metal oxides and hydroxides (for example PbO, ZnO),
and processing aids.
The following examples are given merely to illustrate and not to
limit the present invention.
EXAMPLES 1-15
Tests were carried out to determine the CH.sub.3 Br emissions of
mixes containing the peroxides according to the invention and in
some cases also mercaptobenzothiazole disulphide (MBTS), or
N-phenylmaleimide (NPM) in comparison with the mixes containing
conventional peroxide 2,5-dimethyl-2,5-di-ter.butylperoxy-hexane
(Luperco 101 XL). The tested mixes were all based on terpolymer
P.1, i.e. a terpolymer composed for 66.2% by moles of CH.sub.2
.dbd.CF.sub.2, for 18.2% by moles of C.sub.3 F.sub.6, for 15.2% by
moles of C.sub.2 F.sub.4 and containing bromoperfluorovinylether in
amounts equal to 0.65% by weight of bromine. The ingredients of the
mixes, besides the peroxides and the additives of the types and in
the amounts indicated in Table 1, were the following:
4 p.h.r. of triallylisocyanurate (TAIC) at 75% on an inert
filler,
3 p.h.r. of PbO,
30 p.h.r. of carbon black MT.
the CH.sub.3 Br emissions during the curing step were determined
according to the following modalities:
20 g of finely mixed particles (polymer+fillers) were treated at
180.degree. C. in a closed reactor for 30 minutes at a pressure of
0.5 kg/cm.sup.2 abs. in a N.sub.2 atmosphere.
At the end, the whole was cooled to 40.degree.-50.degree. C. and,
as an internal standard, 1 cc of A 114 (C.sub.2 Cl.sub.2 F.sub.4,
b.p.=4.degree. C.) was added.
The gas phase was mixed and then it was analyzed in a
gas-chromatograph.
Column: POROPAK Q
Temperature: 100.degree. C.
The cure trend was evaluated by determining the .DELTA. torque
(MH-ML) by means of the oscillating disk rheometer (ODR) (Monsanto
type), according to standard ASTM D 2084/81, with "arc.+-.3".
Table 1 shows the results of such determinations, where the
CH.sub.3 Br emissions are expressed as percent reduction of the
standard emission of a mix containing the conventional peroxide
Luperco 101XL (Example 1).
TABLE 1
__________________________________________________________________________
ADDITIVE TORQUE REDUCTION IN % OF EX. PEROXIDE phr phr MH-ML MAX
EMISSION CH.sub.3 Br
__________________________________________________________________________
1 Luperco 101 XL 3 -- 67 0.79 -- *carried for 45% 2 S. 172 1.6 --
65 0.71 95 3 S. 172 1.8 -- 66 0.74 94 4 S. 172 2.0 -- 74 1.05 96 5
S. 172 1.8 MBTS 0.25 71 0.87 100 6 S. 172 1.8 NPM 1.5 75 1.01 98 7
S. 172 - *carried for 40% 4.5 -- 69 0.78 96 8 S. 172 - *carried for
40% 4.5 MBTS 0.25 66 0.66 100 9 S. 173 1.3 -- 50 1.08 95 10 S. 176
- *carried for 40% 5.1 -- 66 1.15 95 11 S. 176 - *carried for 40%
6.8 -- 68 1.24 95 12 S. 176 - *carried for 40% 8.5 -- 68 1.37 94 13
S. 176 - *carried for 40% 8.5 MBTS 0.25 73 1.60 100 14 S. 179 1.5
-- 70 0.95 95 15 S. 185 2.6 -- 60 1.3 98
__________________________________________________________________________
*carried on CaCO.sub.3 /SiO.sub.2 1:1
EXAMPLE 16
Curing tests in mold were carried out to determine the actual
reduction, under real conditions, of the CH.sub.3 Br emissions by
subjecting to gas-chromatographic analysis, under the conditions
indicated in the preceding examples, an air sample drawn above the
molded article immediately after the detach of the vulcanizate from
the mold.
The elastomers utilized in the mixes were the P.1 defined in the
preceding examples and the P.40, which is a terpolymer composed for
54.1% by moles of CH.sub.2 .dbd.CF.sub.2, for 22.2% by moles of
C.sub.3 F.sub.6 and for 22.9% of C.sub.2 F.sub.4, containing
bromoperfluoroethylvinylether in an amount equal to 0.6% by weight
of bromine. Both the mixes and the cured product were characterized
too. The following Tables show the characteristics in comparison
with standard mixes, which contain Luperco 101XL as a peroxide.
In particular, Table 2 indicates the compositions of the tested
mixes and their characteristics.
Table 3 shows the percentages of reduction of the CH.sub.3 Br
emissions and a few characteristic values, which are indicative of
the cure trend.
Table 4 indicates the characteristics of the cured material.
TABLE 2
__________________________________________________________________________
ASTM D. 1646-82 135.degree. C. COMPOSITION OF THE MIX (ASTM D.
3182-82) MOONEY 121.degree.C. Mix poly- carbon SCORCH MOONEY No.
mer peroxide phr TAIC PbO black MV t 15 ML (1' + 10')
__________________________________________________________________________
1 P. 1 LUPERCO 101 XL 3.0 4 3 30 48 13' 36" 103 45% 2 P. 1
PEROXIMON S172 1.8 4 3 30 48 10' 55" 103 PURE (1) 3 P. 40 LUPERCO
101 XL 3.0 4 3 30 12 26' 30" 33 45% 4 P. 40 PEROXIMON S172 1.8 4 3
30 17 20' 30" 42 PURE (1)
__________________________________________________________________________
(1) = bis(1,1dimethylpropyl)peroxide.
TABLE 3
__________________________________________________________________________
CURING CHARACTERISTICS (ASTM 02084-81 - ODR, 180.degree. C.; arc
+/-3) PO- MIX REDUCTION IN % LY- No. (from ML MH ts 2 t'50 t'90 V
max .DELTA. TORQUE OF CH.sub.3 Br EMIS- MER tab. 2) (lbf .multidot.
in) (lbf .multidot. in) (s) (s) (s) (lbf .multidot. in/s) MH-ML
SION
__________________________________________________________________________
P. 1 1 22 80 72 126 360 0.58 58 -- P. 1 2 22 86 66 123 294 0.70 64
92% P. 40 3 4 51 78 -- 399 0.40 47 -- P. 40 4 6 55 75 -- 270 0.60
49 96%
__________________________________________________________________________
TABLE 4
__________________________________________________________________________
MECHANICAL PROPERTIES after post-cure (250.degree. C. + 24 h) ASTM
after press-cure (170.degree. C. + 10') D2240 ASTM ASTM -81 D1414
D. 2240-8 Hard- -78 Hardness ness (*) MIX ASTM D. 412-83 (poi- ASTM
D. 412-83 (poi- C.S. PO- No. Tensile propert. nts) Tensile
properties nts) (%) LY- (from (MPa) (MPa) (MPa) (%) H-Sho (MPa)
(MPa) (MPa) (%) H-Sho O-R MER tab. 2) M100 M200 T.S. E.B. re A M100
M200 T.S. E.B. re A 214
__________________________________________________________________________
P. 1 1 3.7 9.1 12 284 72 5.6 15.9 18.2 233 75 33 P. 1 2 4.4 11.7 14
257 73 6.0 17.7 21.2 231 73 25 P. 40 3 2.4 5.1 6.4 383 66 4.0 10.0
13.4 262 70 44 P. 40 4 3.0 6.3 7.4 339 68 4.4 11.2 14.3 252 71 45
__________________________________________________________________________
(*) C.S. = compression set at 200.degree. C. for 70 hours.
EXAMPLE 17 (COMPARISON TEST)
Curing tests were carried out at 180.degree. C. in a mold, using a
mix having the composition indicated in examples 1 to 15, except
the peroxide, wherein as a peroxide there was utilized a perketale
which, by decomposition, prevailingly formed ethyl radicals and a
few methyl radicals (CH.sub.3 --CH.sub.2./CH.sub.3.ratio=15:1),
having the formula: ##STR5## Said peroxide, which was utilized in
the mixes in an amount of 1.7 p.h.r., led to a viscosity increase
(.DELTA.torque) of only 7 points, against the 67 points obtained by
using Luperco 101XL (see Table 1), what indicates that it did not
cause the cure of fluoroelastomers at 170.degree.-180.degree.
C.
EXAMPLE 18
The peroxide bis(1,1-dimethylpropyl)peroxide (Peroximon S 172) of
formula: ##STR6## was synthesized.
Into a 4-neck flask of 1 liter of volume, equipped with stirrer,
thermometer and an efficient cooler, 400 g of 2-methyl-2-butanol
(4.54 moles) were charged.
After having brought the temperature to 40.degree. C., 115.8 g of
H.sub.2 O.sub.2 at 70% (2.383 moles) and 453.4 g of H.sub.2
SO.sub.4 at 70% (3.236 moles) were simultaneously fed in 60
minutes.
Reaction was stopped after 6 hours by stopping the stirring. After
separation, 318.4 g of rough product were obtained (86.5%
iodometric titre as peroxide), which was then purified by repeated
washings with equal portions of NaOH at 10%. The washed product was
then purified by means of rectification under vacuum, thereby
obtaining 250 g of product at 99.5% of gas-chromatographic
titre.
The obtained product was identified by means of NMR, gas-mass and
iodometric analyses.
EXAMPLE 19
The peroxide bis(1,1-diethylpropyl)peroxide (Peroximon S 173) of
formula: ##STR7## was synthesized.
First step
In a 500 ml flask equipped with stirrer and cooling system, 1 mole
of triethylcarbinol was reacted with 2 moles of H.sub.2 O.sub.2 at
70% in the presence of 1 mole of H.sub.2 SO.sub.4 in a solvent
consisting of 1.3 moles of hexane, at a temperature of 20.degree.
C. for a time of 2-4 hours.
On conclusion of the reaction, the organic phase was separated from
the aqueous phase and neutralization was carried out with 20 g of a
NaOH solution at 1%.
Second step
The organic phase coming from the first step was then additioned
with 1 mole of triethylcarbinol, and to the resulting mixture,
after evaporation of the solvent at 0.degree. C. under vacuum, 2
moles of paratoluenesulphonic acid as aqueous solution at 70% were
added. The reaction mixture was then reacted at 35.degree. C. for
24 hours.
From the reaction mixture, the peroxide was then separated by
decantation of the organic phase and subsequently it was purified
by means of repeated washings with a NaOH solution at 10%.
After filtration and removal under vacuum of the lighter fractions,
a residue was obtained, which consisted of the peroxide
bis(1,1-diethylpropyl)peroxide, which was identified by NMR,
iodometric and gas-mass analyses.
EXAMPLE 20
The peroxide bis (1-ethyl-1-methylpropyl)peroxide (Peroximon S 176)
of formula: ##STR8## was synthesized.
First step
Into a 4-neck flask having a 0.5 liter volume, equipped with
stirrer, thermometer and an efficient cooler, 100 g of
3-methyl-3-pentanol (0.979 moles) were charged. After having
brought the temperature to 30.degree. C., 95.1 g of H.sub.2 O.sub.2
at 70% (1.957 moles) and 137.1 g of H.sub.2 SO.sub.4 at 70% (0.979
moles) were simultaneously charged in 30 minutes.
The reaction was stopped after 3 hours.
After separation of the phases, 112.8 g of 1-methyl-1-ethylpropyl
hydroperoxide at 99% of iodometric titre were obtained.
Second step
Into a 1 liter flask, 112.8 g of hydroperoxide and 100 g of
3-methyl-3-pentanol (0.979 moles) were charged. The whole was
brought to 40.degree. C. and 394.5 g of p.toluenesulphonic acid at
70% (1.603 moles) were fed in 20 minutes.
The reaction was stopped after 18 hours and 120.5 g of a rough
product were obtained. The rough product was purified by means of
repeated washings with NaOH at 20% and then it was rectified under
vacuum: there were obtained 95 g of peroxide at 96% of iodometric
titre, identified through NMR and gas-mass analyses.
EXAMPLE 21
The peroxide 1,1-diethylpropyl, 1-ethyl-1-methylpropyl-peroxide
(Peroximon S 185) of formula: ##STR9## was synthesized.
It was operated in like manner as is described in example 19, with
the exception that in the second step diethylcarbinol was utilized
instead of triethylcarbinol. The peroxide was characterized by
means of NMR, iodometric and gas-mass analyses.
EXAMPLE 22
The peroxide 2,5-dimethyl-2,5-di-ter.amyl-peroxy-hexane (Peroximon
S 179) of formula: ##STR10## was synthesized.
Into a 4-neck flask having a 1 liter volume, equipped with stirrer,
thermometer and an efficient cooler, 176.3 g of 2-methyl-2-butanol
(2.0 moles) and 445.7 g of 2.5-dimethyl-2,5-bis(hydroperoxy)hexane
at 80% (2 moles) were charged.
While maintaining the temperature at 30.degree. C., 280.3 g of
H.sub.2 SO.sub.4 at 70% (2.0 moles) were then fed in 30 minutes.
The reaction was interrupted after 6 hours by stopping stirring and
separating the two phases which were formed. The resulting rough
product (400 g) was repeatedly washed with NaOH at 10% and with
demineralized water in equal amounts.
After rectification under vacuum (residual 11 m of Hg), there were
obtained 350 g of product at 90% (gas-chromatographic titre) which,
by NMR, gas-mass and iodometric analyses, was identified as
2,5-dimethyl-2,5-bis(ter.amylperoxy)hexane.
Although the invention has been described in conjunction with
specific embodiments, it is evident that many alternatives and
variations will be apparent to those skilled in the art in light of
the foregoing description. Accordingly, the invention is intended
to embrace all of the alternatives and variations that fall within
the spirit and scope of the appended claims. The above references
are hereby incorporated by reference .
* * * * *